Compass system



mm. 23, 192% E,52,02

c. H. BEDELL COHPASS' SYSTEM Filed April 27, 1922 351, alien WW M W I E distant that direct observations may be un- Patented Dec 23, lg l. I I v (GHAELEQ E. enema, F NEW LGIWQN, CONNEGTIUU'L", ASSIGN'QR TU ELEGTRIC BOAT @QMPANY, A GDEPQRATION 0F NEW JERSEY.

@QIEEMKS streams.

Application filed April 537, 19%;. Serial No, ssrnaa To aZZ whom it may concern: the compass card on a distantly placed Be it known that l, Cnannns H. Bnnnnn, screen, ordinarily below the compass, in

a citizen of the United States, residing at much the same manner that a stereopticon New London, in the county of New London, slide is projected. As the compass card State of Connecticut, have invented certain serves as the slide it must be transparent new and useful Improvements in Compass with opaque graduations, and the compass Systems; and, I do hereby declare the fol box must permit the passage of light through lowing to be a full, clear, and exact descripit. The lubber line is in the form or an tion of the invention, such as will enable 0thopaque pointer projecting from the side of MD ers skilled in the" art to which it appertains the box. In order that the use of the transto make and use the same. parent card should not interfere with direct This invention relates to a compass system reading from above. the inner face of the for ships, by means of which accurate readcompass box is whitened and a light placed ings may be had of the card from a point so within the binnacle to illuminate this white surface and cause the opaque graduations of satisfactory. the card to stand out in sharp relief so that As is usual in ship construction, iron and they are clearly visible to one reading the steel are extensively used, and the magnetic card from above. compass is placed as far as possible from The lenses of the system are mounted such material. On surface ships the standwithin a tube which extends from a point .ard compass is usually placed at some disadjacent the compass to the screen. In the tance above the pilot house, and a secondary case of a submarine, this tube must, of course, compass within that house is used in the pass through the hull, and in this case, actual working of the ship; allowance-being. should the binnacle spring" a leak the danger made for the difierence in the readings of would arise of flooding the vessel through the two compasses. On submarines, the the lens tube, upon submergence. To guard compass is usually mounted in a watertight against this is a further object of the invenbinnacle of non-magnetic material, above the tion. It is attained by placing a gate valve superstructure, with aheavy plate glass winin the tube so that all communication with dow, so located that the opaque white card the binnacle will be quickly and efi'ectively may be read from the station on the bridge, cut ofi in an emergency, and so placing this and a second opaque white'card placed imvalve relative to the beamof light passing mediately below the other for observation through it, that a valve opening or mini- ,from below. Observation from below has mum size can be used without lnterfering as been either by direct vision assisted by a lens with the operation of the proiecting system.

placed below the compass. or by means of af IWhen a submarine is submerged it is obtelescope. The direct vision method has vious that readings ,of the compass in the proved unsatisfactory, as the distance rebinnacle must be from below, and for this vents accurate reading of the card. he reason the need ofan improved system for so telescope method has also proved unsatis distant reading is more imperative in the factory, for while accurate readingsare obcase of a submarine than in the case of a tained the holding of the eye to the eye surface vessel. The invention has, therefore, piece for long periods of time is very fatibeen describedwith particular reference to guing and interferes with general .observasubmarine use, although it is clear that it is tion 1n the control of the station. not necessarily so limited.

It is therefore an object of the present in- The invention will be more clearly undervention to devise means for projecting an stood by referring to the accompanying image of the compass card to a relatively drawings in wh1chdistant point, in such a manner that the Figure 1 1s a diagram of the optical systo image can be read with both eyes and with tern employed for indirect readings; Figure the same ease and accuracy as the actual card 2 is a vertical section, more or less diagramitself, without at the same time interfering matic, through the binnacle and part of the in any way with direct reading. hull showing a compass mounted for both This object is attained by the use of an direct and indirect reading; Figure 3 is a optical system which projects an image of section on an enlarged scale through the compass box, and Figure 4 represents the yiew of a portion of the compass card as seen on a ground glass screen within the vessel.

In these drawings, 1 represents the hull of the vessel and 2 a watertight binnacle mounted on its upper surface. Within the upper part of this binnacleis mounted the compass 3 comprising a compass card 1 within a compass box, or bowl 5, which box is mounted for universal movement on a gimbal 6. The compass card 4 is made transparent, at least on its periphery and bears an opaque scale. The compass box 5 has a transparent bottom whichpermits of illumination of its interior by means of -a light situated beneath it and also permits reading of the transparent compass card from a point beneath it. 'A, sharp black point 7 is fixed on the inner wall of the compass box 5 andserves as a lubber line, the inner Walls of this box being made white for the purpose of increasing the visibility of this black pointand the compass scale. The knife edge of the gimbal, the compass card and the lubber line point should preferably all be in the same plane so thatthe rolling of the ship will not effectively displace the lubber line with reference to the card.

Direct reading of the compass is afforded through a heavy glass late 8 mountedin an inclined upper face 0 the binnacle. This reading is facilitated by meansof a lamp 9 situated within the binnacle and beneath the compass, the light from this lamp illuminating the whitened inner wall ofthe compass box and producing a bright background upon which the figures on the trans arent card and the black point 7 stand out 5 arply defined. It is clear that anyone standing upon the hull of the vessel during surface cruising can read the compass in the ordinary manner.

In order that this same com ass may be employed when the vessel is en merged, the optical system shown diagrammatically in Figure 1 is employed to project an image of the compass card to a point within the hul of the vessel. This system comprises a lamp 11 mounted above the com ass in the u per part of the binnacle, an having a light source as small as practicable, a palr of condensing lenses 12 and 13 which gather the light rays from this source and pass them in substantial parallelism through an edge portion of the card, two erecting lenses 14 and 15, two projecting lenses '16 and 17, a

. mirror 19 or other suitable reflecting emface placed at an angle of 45 degrees to the axis of the'system, and a ound glass 20 on which the image is fina ly focused. This ima appears. on the ground lass as shown in ig. 4 with the sharp blac point 7 u permost and the scale directly readable. e scale is ordinarily printed on the upper face of the compass card for direct reading.

. 1 The reverse ima e of this scale, as seen from beneath the cars, is reversed by the system and appears on the ground glass in its normal position. v

In accordance with well-known optical laws images of the card are formed at 26 and 20. As it is never possible to obtain a true point source of light, the beams at 25 and 18 are not lines as indicated but have an appreciable diameter dependent upon the size of the filament of lamp 11. By making this filament small and designing the system properly the diameterof the light beam at these points ma is, only a fraction of an inch in diameter. Advantage is taken of this fact in the present invention, as will be explained later.

The lenses of this system are mounted within a lenstube 22 which extends from a point adjacent the compass, through the hull of the vessel, and to some observation point below. The binnacle is made watertight so that at the time of submergence no attention need be given to it. There is, however, the danger that the glass plate 8 may break due to the heavy pressure which it must withstand at times, and there is also the danger that the binnacle may spring a leak from other reasons or be dislodged b a shell. In

such cases the danger arises o flooding the vessel through the lens tube 22. In order to avoid this possibility a gate valve 23 is placed in the tube and so positioned that it may be immediately closedshould necessity arise. By placing'this valve at the oint 18 where the rays from the lamp 11 are rought together by means of projecting lenses 16 and 17 it 18 possible to employ a valve having. a clear opening only one inch in diameter without in any way interfering with the light. A valve having so small an opening is quickly closed and when closed is .more likely to be strong .and leak-proof than a larger valve. The tube 22 may also be provided with a stufling box 24 at a point where it passes through the hull of the vessel to prevent any leakage around it.

A sharp black point 7 projecting from the inner face of'the compass box serving as a lubber line has been shown. During direct reading this black point stands out in clear relief against the white surface of the compass box. During indirect reading it is projected downwardly with the image of the the glass.

By placing the compass without the hull its hence a small actual throw of t e point would appear of much greater magnitu e on neaaooa 0f the vessel, and employing the system described above, it is possible practically to eliminate the disturbing magnetic influences of the vessel and to navigate by a single magnetic compass both while on the surface and while submerged.

The danger of flooding the vessel through the lens tube due to some leakagein the binnacle is entirely avoided by means of the gate valve, and by locating this valve at that part of the tube where the light rays converge it is possible to employ a valve having a very small opening, and hence one which can be more quickly operated and be less likely to leak when closed.

The idea of placing a valve of relatively small openin at a point in an optical system where t e cross-sectional area of the converged light field is small is not neces sarily limited to the present use but may be employed wherever it is necessa to close two sections of such a system from each other quickly and securely.

The optical system used has been shown more or less diagrammatically and no attempt has been made more than to illustrate in general lines the structure of any of the parts. It is clear that other specific means might be employed for attaining the same ends, and that the system may be used on surface ships as well as submarines.

I claim: v v,

1. A compass system for ships, comprising the combination of a transparent-bottom compass box having whitened inner walls and ,an opaque lubber line extending in wardly therefrom, a transparent compass card bearing an opaque scale mounted within the compass box, illuminating means beneath the card illuminating the whitened inner walls of the compass box, thus forming a bright background upon which the compass scale can be easily and directly read from above, and means for projecting an image of the card and lubber line point upon a screen within the vessel.

2. An optical system, designed to project an image of an object situated without a submarine to a point within the submarine, comprising a tube, a series of lenses in said tube so arranged as to gather the light from the object and cause it to converge and then diverge, and means for closing the tube at a place where the cross section of the light field is relatively small.

3. An optical system, designed to project an image of a compass card situated without a submarine to a point within the submarine, comprising a tube, a series of lenses in said tube so arranged as to gather light passing through the card and cause it to converge to a field of relatively small cross section and then diverge, and a gate valve at the point of smallest cross section of the light field having an opening smaller in diameter than the tube and only slightly larger than the diameter of the converged light field.

In testimony whereof I afiix my signature.

CHARLES H.1BEDELL. 

